Despite the advances made in technologies such as medical imaging to assist the physician in the diagnosis and treatment of patients with possible abnormal tissue growth such as cancer, it is still often necessary to physically identify abnormal tissue regions for subsequent surgical removal. One disease for which this approach is a critical tool is breast cancer.
In the detection and treatment of breast cancer, open or excisional biopsies are often advisable when a suspicious tissue mass may need to be removed. In addition, lumpectomy or partial mastectomy may be performed when the tissue mass is cancerous as part of breast conservation therapy (BCT). One technique that is frequently employed to physically identify the abnormal tissue region to be removed is called wire localization. Wire localizations often require a radiologist to manually insert a wire that contains one or more hooks on its distal end into the breast of the patient through a needle and then position the hook region of the wire so that the end of the wire resides within or is adjacent to the suspect tissue requiring surgical removal. The needle is removed and the wire is left in the tissue and the patient is then transferred to the operating room, typically several hours later, to have the suspect or target tissue or lesion removed by a surgeon.
However, such wires are often inaccurately placed, and once placed they are prone to migration, and cannot be easily adjusted once they have exited the needle. Moreover, even if the wire has been properly placed, the surgeon often cannot intraoperatively identify the tip of the wire, which can result in the surgeon removing a larger portion of tissue than is necessary to optimize the chances for cancer-free margins of the tissue specimen that is removed. Also, if the suspect tissue mass is not found at the end of the wire, the surgeon often ends up cutting or removing non-afflicted tissue without removing the lesion. In addition, after placement but before the surgical procedure, the wire protrudes stiffly from the body and can become dislodged or migrate to position remote from the originally demarcated region of identified tissue. While the localization wire resides in the patient awaiting surgery, the wire can be uncomfortable and cannot be adequately secured in a manner that would permit the patient to sleep overnight without discomfort or without a high risk of dislodgement. Because of these risks associated with migration and patient discomfort, the patient must proceed with the surgical removal of the lesion the same day as the placement of the localization wire. In addition, logistical delays between placement of the wire and eventual surgical excision can exceed several hours, leading to additional discomfort and risk of migration.
Another drawback of current localization wires is the need to pass the needle and wire through the lesion leading to potential transmission of cancer cells, sometimes referred to as needle tract seeding.
Therefore, a solution is needed that can accurately and removably place a localization or marking device into a patient to demarcate a region of tissue for subsequent surgical removal. Such a solution should reliably define the border of the tissue to be removed and reduce the risk of inadvertent migration, even over a period of hours or days.